With the continuous development of communication network technologies, when a communication network is utilized to transmit information streams, the communication network can also be utilized to transmit currents to supply power to electrical equipment in the network. For example, power is supplied to electronic equipment, such as network telephones, wireless access points, surveillance cameras, terminal switching equipment, etc. in a network, by using the Ethernet. As another example, power is supplied to electronic equipment, such as telephones, ever-burning lamps, environmental monitoring equipment, etc. in a telephone network, by using the telephone network. Using the communication network to supply power to the equipment solves the problem of difficulty in power acquisition, improves the flexibility for the usage of the equipment, and reduces the installation complexity of the equipment itself and the usage cost. In addition, power supply or outage of equipment can also be controlled remotely by using the communication network.
As the communication network power supply technology is widely used, there are higher power demands for electrical loads in the communication network. To achieve higher power of communication network power supply, usually two or more than two power sourcing equipment will be used to supply power to the same electrical load. When an interface controller receives power from the power sourcing equipment, the power first passes through a current sharing module to make magnitudes of currents in two or more than two power supply lines same, and then passes through a direct current/direct current (DC/DC) converter to be output to the electrical load. Due to differences in power supply distances of the power sourcing equipment and loss in the power supply lines, there is a problem of large voltage difference between each port of the interface controller. The related technical scheme compensates for the voltage difference between all input ports by performing non-DC-to-DC conversion on each input port voltage (e.g., using linear voltage conversion similar to a low dropout regulator (LDO), and a voltage division manner by the series resistors), to achieve current sharing. However, the voltage compensation range of this method is limited, resulting in poor current sharing. Additionally, the greater the pressure difference of the input ports is, the greater the loss is and the lower the efficiency is. In the related technical scheme, there is a method where each power supply line corresponds to one DC-DC voltage converter to achieve current sharing. With the increase of the power supply lines, the number of DC-DC voltage converters increases and the cost will be greatly increased. When power supply time of a plurality of power sourcing equipment are different, electric energy output by each power sourcing equipment cannot be averaged, and the fairness of power supply cannot be realized.